Which method is most effective for destroying insects in stored grains, spraying or fumigation?

Explanation

### Step-by-Step Solution:

1. **Understanding the Problem**: We need to determine which method, spraying or fumigation, is more effective for destroying insects in stored grains.

2. **Identifying the Methods**:
- **Spraying**: This method involves applying insecticides in liquid form directly onto the grains and the surrounding area.
- **Fumigation**: This method uses insecticides in gaseous form to treat the grains and the storage area.

3. **Analyzing the Effectiveness**:
- **Spraying**: While spraying can kill insects on the surface of the grains, it may not penetrate deeply into the grains or reach insects hidden in crevices or corners of the storage area.
- **Fumigation**: Fumigation, on the other hand, disperses the insecticide in gas form, allowing it to penetrate all areas, including those that are hard to reach. This ensures that insects hiding in the grains or the storage area are effectively targeted.

4. **Conclusion**: Based on the analysis, fumigation is the more effective method for destroying insects in stored grains because it provides comprehensive coverage and penetrates deeper than spraying.

5. **Final Answer**: Fumigation is the most effective method for destroying insects in stored grains.